A roof flashing structure is improved by shaping the uppermost periphery of the housing of the flashing such that an elastomeric sealing member can be molded onto the housing and be retained therein by a combination of both a mechanical lock and a thermal bond.
In my prior U.S. Pat. No. 4,010,578 and my patent application Ser. No. 883,420, I described certain roof flashing structures having features which provide them with advantages not found in the old type of flashing structures made of sheet metal and which were sealed to a pipe with calking or other mastic-type materials. While my prior roof flashing structures are improvements over the sheet metal-type previously used it has been found that the plumbers and other construction personnel who install them have a tendency to dislodge the sealing rings from the housing during installation thereof.
For adequate service the housing of a roof flashing structure must be formed of a stiff, resilient material which will maintain its proper shape during both the cold of winter and the heat of summer. However, the sealing member must be formed of a flexible material which can conform with and form a tight seal against the surface of the pipe which moves within the seal as it expands and contracts.
The prior roof flashing structures simply do not meet the criteria wherein the housing and the sealing member must be formed of different types of materials because of their functions and the criteria of a one piece structure having no separate parts which can be lost or dislodged from one another by overzealous construction personnel.